交会图在控缝高压裂影响因素分析中的应用

江汉油田潜4^3油组普遍具有油层薄、隔层薄的特点,属于低渗透油藏的第二、三类差储藏,压裂控制缝高难度较大。统计现场压裂施工效果,结合储层岩性特征并应用交会图图版法分析压裂因素,发现影响缝高控制的因素很多,除地应力、储层的杨氏模量、断裂韧性等地质参数外,施工排量、压裂液黏度、前置液量、支撑剂量等因素也可影响裂缝高度的增长。不能仅考虑地质因素或工程参数某一个影响因素,应综合多种因素分析研究。     

斜拉跨越结构的优化分析

考虑斜拉索直径、塔架高度和斜拉索与塔架连接间距三方面因素,利用有限元法对斜拉跨越的结构形式进行优化分析。结果表明,斜拉索的尺寸变化对结构的强度影响不大,而对结构的变形影响很大,其中斜拉索的直径以从管架桥中间到两边逐渐减小的分布形式最好。塔架高度变化对结构的变形影响不大,而对结构的强度影响很大,塔架高度为46m时结构的强度更好。斜拉索与塔架的连接间距变化对结构的变形影响很小,而对结构强度影响很大,当间距为7.5×10-2 m时结构的强度更好。     

未知环境中自主机器人的路径规划研究

未知复杂环境中自主机器人合理的路径规划是进行探索任务的前提.传统的路径规划方法侧重于研究从起始点到目标点的无碰路径,很少考虑机器人自身运动的平稳性.研究了室外未知环境中考虑机器人姿态稳定性以及能量损耗的路径规划方法,该方法分三步:(1)梯度计算,计算运动区域的梯度;(2)节点探测,运动区域被划分为平坦区域和非平坦区域,辨识每个平坦区域的中心位置,即节点;(3)路径评估,根据提出的评估函数,规划出从当前位置经过中间节点到目标点的最优路径.结合机器人的动力学特性,利用反演控制,设计了合适的控制率,保证了机器人的平稳运动.通过和传统规划方法获得的路径比较,仿真验证了所提方法的有效性.     

Height of fractured zone inside overlying strata under high-intensity mining in China

The height of fractured zone(HFZ) at the high-intensity longwall mining panel plays a vital role in the safety analysis of coal mining under bodies of water. This paper described definitions of the highintensity mining. The processes of overburden failure transfer(OFT) were analyzed, which were divided into the development stage and the termination stage. Through theoretical analysis, the limited suspension-distance and the limited overhanging distance were proposed to judge the damage of each stratum. Mechanical models of strata suspended integrity and overhanging stability were established.A theoretical method to predict the HFZ at the high-intensity longwall mining panel was put forward based on the processes of OFT. Taking a high-intensity longwall mining panel(No. 11915 panel) as an example, the theoretical method proposed, the engineering analogy and the empirical formulas in the Regulation were used to predict the HFZ. The results show that the theoretical result is consistent with the engineering analogies' result and empirical formulas' result. The rationality and reliability of the theoretical method proposed is verified.     

钟摆钻具扶正器安放高度计算

钟摆钻具是一种常用的纠斜钻具组合,在钻井中应用极为广泛。文中对石油工业部１９８７年颁布的“直井部钻具组合设计推荐方法”中的钟摆钻具扶正器理想安放高度计算公式进行了推导,对公式的简化,和学模型进行了分析,并结合实例探讨了该公式的实际应用价值。这对进一步理解钟摆具扶正器理想安放高度的设计方法和指导现场应用具有一定的参考价值。     

Reprint of: Requirements of 3D cadastres for height systems

Three-dimensional (3D) cadastral systems can only be built if there are suitable height reference systems. However, the earth is neither homogeneous nor flat, and the plumb lines are curved and not parallel. Thus, the definition of height and the implementation of geodetic height systems are complex. 3D cadastres must connect to the existing national height reference. In addition, cadastral systems are designed to persist for centuries. Over such long periods, the earth changes, from plate tectonics, erosion, human intervention, etc. Changes in the technology of measurement equipment can also occur, allowing different definitions. These considerations are important in the design of a 3D cadastre. At minimum, the height system used for the cadastre must be well-defined, to enable adjustments from potential changes in the height system or even the actual point heights.This study examines existing height systems and the determination of height in the context of cadastral tasks. Accuracy requirements for height in a 3D cadastre are analyzed using typical examples. The selected height system must support these requirements. This study also develops the questions that must be answered and highlights the problems that can emerge in some of the solutions. There is no height reference system that fits all needs, and each solution has advantages and disadvantages. Different systems may be optimal for different countries. It may also be beneficial to allow different geometrical qualities for different parts of a country.     

A Simple Model for Estimating Return Values of Wave Heights

A simple statistical model is used to estimate the 50-year return value of significant wave heights at El-Dabaa. This value is required for immediate application. The estimated value was about 7 r m. The results obtained through application of this model are helpful for engineers who are interested in the design and construction of offshore installations.     

THE EFFECT OF WAVE GROUPINESS ON A MOORED SHIP STUDIED BY NUMERICAL SIMULATIONS

Waves with the same wave parameters, such as significant wave height and period, but with different wave groupiness factors are simulated, to study the motion behavior of a moored ship under the action of waves with different Groupiness Factors of Height (GFH) and Group Length Factors (GLF). The numerical results show that both the sway and heave motions increase with an increase in GFH. In contrast, the influence of GLF on the motions of a moored ship is weak.     

张楚汉院士称:白鹤滩水电站综合技术指标居世界前列

从每一个单项来说,白鹤滩水电站的指标都不是最高的,但综合了库容等五个方面的指标,其综合难度就处于世界前列。在世界上,270 m到300 m等级的高拱坝设计建设中,遇到这么多的高指标,并不多见,白鹤滩工程必将带动我国高拱坝建设水平的进一步提高。     

FA022型多仓混棉机延时混和分析

分析了ＦＡ０２２型多仓混棉机采用自然梯度喂料时相邻棉仓存料差喂料循环的变化过程,得出了混和延时的数学表达式及混和延时与该机的仓数、光电管的安装高度等参数间的关系;找出了提高混和效果的技术措施。并分析了该机的输入量、输出量及棉仓个数与光电管的安装高主的关系,计算出了不同参数时光电同度值。